Chlorinated polyvinyl chloride (CPVC) is a thermoplastic polymer prepared by chlorinating polyvinyl chloride (PVC) resin. As CPVC contains more amount of chlorine as compared to PVC, the former is more tolerant to wider temperature ranges and demonstrates improved resiliency in terms of conveying both hot and cold materials. Consequently, CPVC has a wide range of industrial applications including pipes used for hot and cold water distribution in residential and industrial use, transportation of corrosive liquids, high tension cable protection pipes and the like.
CPVC is typically prepared by the chlorination of PVC by means of a photo-chemical reaction. The photo-chemical reaction is initiated by an irradiation source, wherein the photons emitted from the source decompose the chlorine gas to generate free radicals of chlorine which upon reacting with PVC replace a portion of the hydrogen in the PVC with chlorine to yield CPVC.
Preparation of CPVC with improved properties such as thermal stability, colour and inherent viscosity necessitates a specific grade of PVC as the starting material, for instance, PVC with higher porosity, higher inherent viscosity, higher thermal stability and lower yellowness index. However, procuring PVC having the afore-stated properties results in a higher running cost of the operation. Furthermore, the CPVC that results from such an expensive means is often vulnerable to decomposition and outwardly defects mostly arising due to a longer time of reaction and certain mutations in the form of double bonds, conjugation of double bolds or unsaturations.
A need is therefore felt for developing a process for preparation of CPVC which mitigates the afore-stated drawbacks.